1. Field of the Invention
The present invention relates to the field of apparatus and methods for the treatment of fractures, and more particularly to an apparatus and method providing a portable, dynamic traction assembly for the treatment of a fracture.
2. Description of the Prior Art
There have been a great number and variety of methods and apparatus for the treatment of bone fractures, many of these being specialized for the treatment of particular fracture sites and types. The proper setting of a fracture to provide proper healing and rejoining of the bone sections frequently employs a pin or other artificial device to be achored into the bone sections so that the tendency of the sections to remain apart or misaligned can be overcome. While certain fractures can be treated simply with an externally applied, plaster cast, others require the use of pins to assure proper alignment of the bone sections.
The present invention relates to the treatment of a fracture of the distal radius, known more particularly as a Colles' fracture. It has been recognized that the pull of the long flexor and extensor tendons which extend to the fingers and thumb apply a compressive force in the area of a Colles' fracture, and this will interfere with the proper loction and healing of the bone fragments unless offset. Consequently, various methods of treatment have been employed which attempt to offset these forces, while other methods and apparatus simply ignore the forces.
Methods which have been conceived to offset these compressive forces of the flexor and extensor tendons have taken several forms. One approach is to hospitalize the patient and to apply skeletal traction by a system of weights and pulleys following reduction of the fracture. This technique is of course very inconvenient and expensive for the patient. Another approach has been to reduce the fracture and to insert pins through a metacarpal distal to the fracture and through the ulna proximal to the fracture, with both of these pins being incorporated into a plaster cast for rigid fixation. This procedure has the disadvantage of allowing less exercise of the fingers due to the restrictions of the cast and pins, and does not provide any dynamic elastic forces to counterbalance the forces of the tendons.
Another method of pin fixation has been provided by the use of various devices. Typically, these devices involve the placement of a first pin in a metacarpal distal to the fracture and a second pin in the radius proximal to the fracture. The pins are then connected by a device which spans therebetween, and the relationship between the pins is either a rigid fixation or a fixation providing for limited pivoting movement. An example of such a device is contained in U.S. Pat. No. 1,789,060, isued to Weisenbach on Jan. 13, 1931. This patent shows a clamp for a bone fracture in which several pins are anchored into the bone sections on opposite sides of the fracture. The pins are connected by clamps which are joined pivotally to permit relative movement between the pins on opposite sides of the fracture. Similar such devices providing for rigid fixation by interconnection of pins mounted on opposite sides of the fracture, and typically involving compressive forces to maintain the fracture in place, are disclosed in the following U.S. Pat. Nos. 583,455, issued to Bush on June 1, 1897; 1,201,884, issued to Overmeyer on Oct. 17, 1916; 2,333,033, issued to Mraz on Oct. 26, 1943; 3,244,170, issued to McElvenny on Apr. 5, 1966; 3,835,849, issued to McGuire on Sept. 17, 1974; and 3,862,631, issued to Austin on Jan. 28, 1975.
In U.S. Pat. No. 2,091,643, issued to Longfellow on Aug. 31, 1937, there is shown a surgical counter traction splint which includes pins or wires extending through the bones of a limb and applying pressure to extend the bones in a traction manner. The Longfellow device is a fairly complicated one involving several sliding and threaded elements connected together. A similar type of apparatus is shown in each of U.S. Pat. Nos. 2,035,952, issued to Ettinger on Mar. 31, 1936, and 2,024,325, issued to Allen on Dec. 17, 1935. Other devices of only general interest which are intended for locating the relative placement of fractured bones to permit healing are disclosed in U.S. Pat. Nos. 1,933,825, issued to Sloan on Nov. 7, 1933; 4,102,339, issued to Weber et al. on July 25, 1978; 3,877,424, issued to Murray on Apr. 15, 1975; and 1,662,758, issued to Nicholson et al. on Mar. 13, 1928.
In an article entitled "Skeletal Traction Methods" by Mays et al. appearing in Clinical Orthopaedics and Related Research, Vol. 102, July-August 1974, p. 144-151, there is described a method for the treatment of a communited intra-articular fracture of the distal radius which includes a traction technique employing a bow secured within a plaster cast mounted on the forearm. The Mays et al. technique is similar to that of the present invention in that it does employ bone screws mounted to the second metacarpal and also to the ulna, mounts a plaster cast on the person's forearm and secures a wire bow in the cast, and then attaches a rubber band between the bow and the metacarpal pin to apply the traction force. However, the Mays et al. technique is only generally described, with no details given as to the particular materials and their configurations as used in the technique.
Also of interest to the present invention are the following patents. In U.S. Pat. No. 2,485,531, issued to Dzus et al. on Oct. 18, 1949, there is described a surgical toggle bolt used in bone fixation and which includes a J-shaped member to operate as a handle for turning the device. A hip joint prosthesis and associated bone screw are described in U.S. Pat. No. 3,781,917, issued to Mathys on Jan. 1, 1974. The Mathys bone screw is typical of prior art bone screws and includes a grooved head to receive a screwdriver. A different type of bone screw is disclosed in the Bush patent, U.S. Pat. No. 583,455, issued on June 1, 1897. The Bush bone screw includes a thumb-nut or wing-nut secured at one end to assist in manipulation of the screw. In U.S. Pat. No. 4,037,592, issued to Kronner on July 26, 1977, there is disclosed a guide pin locating tool and method for guiding a bone screw during placement within a bone.
It has also been indicated that certain techniques for treatment of a Colles' fracture have failed to take into account the disadvantages associated with the elastic compression forces applied across the fracture area by the long flexor and extensor tendons to the fingers and thumb. These forces tend to deform the fracture reduction and frequently cause loss of position of the fracture fragments. One method of treatment along these lines has been simply a closed reduction of the fractures and an application of a cast to immobilize the fracture. In practice, it is typically observed after a few weeks that there is a gradual loss of position of the bone fragments as exercises of the fingers and thumb are done in the initial period of healing.